Three-dimensional printing system

ABSTRACT

A three-dimensional printing system including at least one positioning mechanism, and at least one end effector movably connected to the at least one positioning mechanism. The at least one end effector includes at least one mixing head configured to dispense a material, and at least one subtractive tool configured to subtract at least a portion of the material such that a desired design is achieved.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a non-provisional application based upon U.S. provisional patentapplication Ser. No. 62/365,130, entitled “THREE-DIMENSIONAL PRINTINGSYSTEM”, filed Jul. 21, 2016, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to three-dimensional printing, and, moreparticularly, to 3D printing and surface finishing of plural componentmaterial molds or objects.

2. Description of the Related Art

Three-dimensional (3D) printing, also known as rapid or additivemanufacturing, is a class of manufacturing that allows for theproduction of physical three-dimensional objects based from computerdesign data. Generally, methods of additive manufacturing technologyemploy the use of a 3D printer to extrude a given materiallayer-by-layer to construct an intricate 3D object. The layer-by-layerprocess may also create a 3D object which is aesthetically unpleasing.3D printing has numerous advantages over traditional manufacturing,which can lead to a more cost-effective and rapid method ofmanufacturing.

Although 3D printing has numerous advantages, at times the process of 3Dprinting renders the 3D object unfit. The layer-by-layer process cancreate a 3D object with an undesirable surface finish. Further, inprinting with certain materials a 3D object may be structurally unsoundor impractical to manufacture if it was to be created solely through anadditive process. 3D printing with a plural component material is notSui generis when it comes to the above-mentioned pitfalls; it suffersfrom the same issues, which can often lead to 3D objects that cannotpractically be used in subsequent manufacturing.

What is needed in the art is a cost-effective system and method forprinting and surface finishing a mold.

SUMMARY OF THE INVENTION

The present invention provides a 3D printing system and method forproducing a quick curing, plural component material mold by usingadditive and subtractive measures according to computer design data.

The present invention in one form is directed a three-dimensionalprinting system including at least one positioning mechanism, and atleast one end effector movably connected to the at least one positioningmechanism. The at least one end effector includes at least one mixinghead configured to dispense a material, and at least one subtractivetool configured to subtract at least a portion of the material such thata desired design is achieved.

The present invention in another form is directed to a three-dimensionalprinting system. The three-dimensional printing system includes a firstpositioning mechanism, a second positioning mechanism associated withthe first positioning mechanism, and a first end effector movablyconnected to the first positioning mechanism. The first end effectorincludes at least one nozzle which is configured for dispensing amaterial layer-by-layer to form a mold. The three-dimensional printingsystem further includes a second end effector movably connected to thesecond positioning mechanism. The second end effector includes at leastone subtractive tool which is configured for subtracting at least aportion of the mold.

The present invention in yet another form is directed to a method for 3Dprinting. The method includes the steps of providing a three-dimensionalprinting system. The three-dimensional printing system includes at leastone positioning mechanism, and at least one end effector movablyconnected to the at least one positioning mechanism. The at least oneend effector includes at least one mixing head configured to dispense amaterial, and at least one subtractive tool configured to subtract atleast a portion of the material. The method includes the further stepsof depositing the material by the nozzle layer-by-layer to form a mold,and subtracting the material by the subtractive tool to subtract atleast a portion of a surface of the material in order to achieve adesired design on the mold.

An advantage of the present invention is that a plural componentmaterial mold can be cost-effectively and readily created according toan intricate computer design model.

Another advantage of the present invention is that at least one mixermay dynamically alter various properties of the plural componentmaterial mold during operation of the three-dimensional printing system.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a perspective view illustrating the 3D printing systemaccording to the present invention;

FIG. 2 is perspective view illustrating an end effector of the 3Dprinting system;

FIG. 3 is a front view illustrating the end effector as shown in FIG. 2;

FIG. 4 is a perspective view of another end effector of the 3D printingsystem;

FIG. 5 is a side view of the end effector as shown in FIG. 4;

FIG. 6 illustrates a schematic of the chemical component proportioningsystem; and

FIG. 7 is a perspective view illustrating a 3D printed mold according tothe present invention.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there isshown an embodiment of a three-dimensional (3D) printing system 10 thatincludes at least one positioning mechanism 12, 14, and at least one endeffector 16, 18 that is movably connected to the at least onepositioning mechanism 12, 14. The at least one end effector 16, 18 mayinclude at least one mixing head 20 and at least one subtractive tool22. The three-dimensional printing system 10 may be configured for 3Dprinting a urethane material, such as a plural component material. Thethree-dimensional printing system 10 may be configured to produce a 3Dobject 24 (FIG. 7) by an additive and subtractive process.

The three-dimensional printing system 10 may include one or morepositioning mechanism(s) 12, 14. In the embodiment of a singlepositioning mechanism, the positioning mechanism may include an endeffector that has a first end in connection with the mixing head 20, anda second end in connection with the milling tool 22. Thereby, the mixinghead 20 and the milling tool 22 may be mounted to the respective ends ofa single end effector. The single end effector may orient the mixinghead 20 and milling tool 22 for a given application. The singlepositioning mechanism may also have an end effector that mounts aplurality of mixing heads 20 and/or milling tools 22. For example,additional mixing heads 20 may be used to spray or pour other pluralchemical component materials.

In another embodiment, three-dimensional printing system 10 may includea first and a second positioning mechanism 12, 14. The positioningmechanisms 12, 14 may respectively have end effectors 16, 18 whichinclude the mixing head 20 and the subtractive tool 22. It should beappreciated that the positioning mechanisms 12, 14 may be locatedproximate to one another along a fabrication line or the positioningmechanisms 12, 14 may be located spatially distant from one another, forexample, the processes of 3D printing plural component material andsubtracting the plural component material may occur in separatelocations.

The positioning mechanism(s) 12, 14, as shown in the present embodiment,may be in the form of robotic arm(s). Each robotic arm 12, 14 may havean end to which the single or respective end effector 16, 18 is moveablyconnected. Additionally, the one or more positioning mechanism(s) 12, 14may be secured to the floor, a gantry, vehicle, track, or drone. It ispossible to use a large boom in conjunction with the positioningmechanism(s) 12, 14, which may additionally include a positioning systemto assist the deposition of material, in order to create a desired 3Dobject. Further, it also possible to use a single positioning mechanism12 or a plurality of positioning mechanisms 12, 14. For example, the useof swarm manufacturing may be employed in which numerous robotic armsare used to create the desired 3D object (not shown).

The first and second end effectors 16, 18 may be movably coupled to therobotic arms 12, 14, respectively, by couplings known in the art. Theorientations of the end effectors 16, 18, and thereby the mixing head 20and subtractive tool 22, may be mechanically or automatically positionedby a control unit in order to produce the desired 3D object 24. One orboth of the end effector(s) 16, 18 may also mount a plurality of mixingheads 20 and/or subtractive tools 22. For example, additional mixingheads 20 may be used to spray or pour other plural chemical componentmaterials. It is also possible to have an end effector which includes apositioning system mounted to it in order to provide real-time feedbackof location, flow rate, current condition and position of the mixinghead 20 or subtractive tool 22, and atmospheric conditions.

Referring now collectively to FIGS. 1-3, there is shown the first endeffector 16. The at least one mixing head 20 of the end effector 16 maybe configured to dispense a plural component material layer-by-layer toform the mold 24 (FIG. 7). The material may consist of single or pluralcomponents. For example, the material may be composed of at least twocomponents including an activator mixture and a resin mixture.Additionally, for example, the material may be in the form of a foam. Ifthe material is composed of plural components, then the mixing head 20may be configured to mix the material and dispense the material. Themixing head 20 may be in the form of a purge gun, such as an airpressurized, hydraulic, mechanical, or solvent purge spray gun. Themixing head 20 may also be in the form of a spray or pour nozzle 20.

Referring now to collectively to FIGS. 1 and 4-5, there is shown thesubtractive tool 22 of the end effector 18. The at least one subtractivetool 22 is configured to subtract at least a portion of the materialafter it has been printed by the mixing head 20. For example, the leastone subtractive tool 22 may be configured to subtract at least a portionof the material from a surface of the mold 24 such that a desired designis achieved in the surface of the mold 24. The subtractive tool 22 mayalso be configured for cutting out entire sections of the mold 24. Thesubtractive tool 22 may be in the form of a milling tool 22. The millingtool 22 includes a motor 26 and an end-milling tool in the form of adrill bit 28. The milling tool 22 may be air or water-cooled. If themilling tool 22 is water-cooled, a cable for water-cooling may bebundled in an existing hose assembly of a mixing head (not shown). Othertypes of end-milling tools may also be used, including various bits,lasers, air or water jets, sanders, etc. to shape or alter the 3D object24. The various end-milling tools may be manually or automaticallyinterchanged during a given application.

Referring now to FIG. 6, there is shown a chemical componentproportioning system 30 that may be operably coupled to the at least onemixing head 20 and configured to heat, pressurize, and proportion thematerial. The proportioning system 30 may include one or morereservoirs, which may heat and pressurize the one or plural componentmaterial. Additionally, the proportioning system 30 may include variousreservoirs, pumps to move the fluid from the reservoirs, valves,heaters, and hoses.

In the present embodiment, the material is a plural component materialand the proportioning system 30 includes two subsystems, for example, anA component system 32 and a B component system 34 for respectivelystoring, heating, transporting and/or proportioning an A componentand/or a B component. The proportioning system 30 pressurizes eachcomponent of the material to a designated psi, and the proportioningsystem 30 provides a desired ratio of the components A and B of thematerial. Also, the proportioning system 30 may provide real-timefeedback of various chemical characteristics including viscosity, flowrate, pressure, temperature, etc.

The A and B components may together comprise the material (e.g. a foam).The A component may be an activator mixture and the B component may be aresin mixture. For example, the A component may be in the form of anisocyanate mixture, and the B component may be in the form of a polymer,e.g. a urethane, mixture. The B component may include an accelerant forcuring the material and a blowing agent, e.g. water, for controlling thedensity and strength of the material.

The A and B component system 32, 34 may each include a single reservoir36A, 36B for housing the respective A and B components. For example, thesingle reservoir 36B of the B component system 34 may house both of theaccelerant and blowing agent. Additionally or Alternatively, the Bcomponent system 34 may include two respective reservoirs 38, 40 forindividually housing the accelerant and blowing agent (FIG. 6). In thisregard, the reservoirs 38, 40 may selectively provide the accelerantand/or blowing agent via pumps in order to alter the various chemicalproperties of the material. For example, the proportioning system 30 mayselectively adjust the blowing agent depending upon a desired density ofthe material such that a material density of at least a first portion ofa first layer of material is different than a material density of atleast a second portion of a second layer of material. Further, thedensity and other material properties may be adjusted within a givenlayer such that a first portion within a layer has a different densitythan a second portion within the same layer. Thereby, the density of thematerial may be altered, for example between approximately 7-60 poundsper cubic foot, in certain layers or sections of the mold 24 in order toprovide for a single mold 24 which may accommodate various load demands.

In another embodiment, the proportioning system 30 may further includean electronic control unit (ECU) and mixers 42, 44. The ECU may beconfigured for selectively controlling the A and B component systems 32,34. The ECU may be operably coupled to the reservoirs and/or pumps ofeach system and/or to the mixers 44, 46 in order to proportion the A andB components. Additionally, the ECU may selectively adjust theaccelerant and/or the blowing agent of the B component. The ECU may bein the form of any desired control unit or processor.

The first mixer 42 may be configured for mixing the accelerant andblowing agent of the B component. The first mixer 42 may be fluidlyconnected to the second mixer 44 and located upstream of the nozzle 20.The second mixer 44 may be configured for mixing the A and B componentsfrom each system 32, 34. The second mixer 44 may be fluidly connected tothe nozzle 20 and located downstream of the first mixer 42 and upstreamof the nozzle 20 of the first end effector 16 (FIG. 6). As shown inFIGS. 1 and 3-4, the end effector 16 may include a frame forrespectively mounting the first and second mixers 42, 44. Also, the endeffector 16 may include a motor 46 for driving both of the mixers 42,44. For brevity of description, the flexible hose connections betweenthe mixers 42, 44 and the various other electrical wiring have beenhidden from view in FIGS. 2 and 3. It is conceivable to have an endeffector 16 which does not mount the mixers 42, 44 and motor 46.

The proportioning system 30 may modulate the flow of the A and/or Bcomponent. In the present embodiment, for example, the flow rates of theblowing agent and accelerant may be adjusted on the fly in order toalter the strength and density properties of the material. For example,the density and strength properties of the material, between multiplelayers or within a given layer, may be adjusted to accommodate a neededvoid in the mold 24 or a cutout in the mold 24 which is to be subtractedby the milling tool 22. Thereby, a lighter weight material could be usedfor the majority of the mold 24 and a higher density and strengthmaterial may be used in the areas of the mold 24 where the void orcutout is located. For instance, the ECU of the proportioning system 30may increase or decrease the flow rate of the blowing agent to cause thematerial being deposited to be of a lower or higher density. Thisdynamic adjustment of the density and strength of the material viaadjusting the accelerant and/or blowing agent as the material is beingdeposited by the nozzle 20 may guarantee the integrity of the mold 24after the cutout material is removed by the milling tool 22 in asubsequent step.

In operation, components A and B may be transported to the proportioningsystem 30. The proportioning system 30 may individually pressurize thecomponents A and B of the material, for example between 150-200 psi, andheat one or both of the components A and B to a specified temperature.The A and B components may also be transported through the hoses to themixing head 20, where the mixing head 20 mixes the components A and Band forces them down in a desired pattern. The positioning mechanism 12then maneuvers the end effector 16, according to a preprogramedpositioning dataset, to spray the material layer-by-layer. Sufficienttime for the material to set in between each pass may be allocated bythe positioning mechanism 12. During, before, or after each pass, theproportioning system 30 may include a step of selectively adjusting theblowing agent depending upon a desired density of the material. In thisregard, the mold 24 may have differing densities among its variouslayers. The mold 24 may also have differing densities and strengthsamong various sections, which are not bound to any particular layer(s).At any time before, during, or after spraying the material the mixinghead 20 may purge the component material by using a solvent flush,through the interior parts of mixing head 20 to flush out cured oruncured materials. In doing so the positioning mechanism 12 may purgesuch materials in a designated area dedicated for waste. Also, prior todepositing each layer, a “waste shot” may be performed to initializemixing and ensure that the desired characteristics of the material arepresent. After a specified number of layers of material, the subtractiveprocess may begin. In the embodiment of a single positioning mechanism,the end effector may be rotated to initiate a tool change in order toemploy the milling tool 22. In the embodiment of two more positioningmechanisms 12, 14, the mold 24 and/or the positioning mechanism 14 maybe moved such that the milling tool 22 of the positioning mechanism 14may operate on the mold 24. The milling tool 22 may then cut thematerial to remove sections of the mold 24 or to form a desired pattern,smoothness, or texture (FIG. 7). For example, the milling tool 22 maycut a desired design in the surface of the mold. The desired design maybe in the form of a pattern, shape and/or texture. This desired designmay be used to mold a corresponding design in a casting material whichis subsequently deposited into the mold 24. Thereby, the method mayinclude the additional step of filling the finished mold 24 with aparticular casting material. For example, the mold 24 may be filled withconcrete in order to mold the concrete into a particular shape or toform an intricate design on the surface of the concrete. Additionalsupport bracing may be provided to prevent deflection when backfillingthe 3D printed mold 24 with the casting material. It should beappreciated that the finished 3D printed mold 24 may be backfilled withany desired material.

This layer-by-layer additive and subtraction process may be repeateduntil the entire 3D printed mold 24 is built according to thespecifications of a preprogramed computer model. The mold 24 mayuniquely match a desired density pattern for different strengths withinthe mold 24 which is provided by a preprogramed computer model. The 3Dprinted mold 24 may also be coated, automatically by the 3D printingsystem 10 or manually, with various finishing coatings.

The flow rates of the proportioning system 30 may be set from thepreprogramed computer model so that the material flow matches the lineartrack speed of the positioning mechanism(s) 12, 14. As the positioningmechanism 12, 14 speeds up and slows down to add material to thedifferent parts of the mold, the individual ingredient flows may alsomodulate to match the speed of the position mechanism 12, 14. Thisallows the printing system to speed up and slow down as needed in orderto accommodate various parts (e.g. more complex features) of thepreprogrammed model. The material flow rate may follow these needs toadd the correct amount of material for each layer or subsection within agiven layer.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

What is claimed is:
 1. A three-dimensional printing system, comprising:at least one positioning mechanism; and at least one end effectormovably connected to said at least one positioning mechanism andincluding at least one mixing head configured to dispense a material,and at least one subtractive tool configured to subtract at least aportion of said material such that a desired design is achieved.
 2. Thethree-dimensional printing system of claim 1, wherein said at least onemixing head dispenses said material layer-by-layer to form a mold. 3.The three-dimensional printing system of claim 2, wherein said at leastone subtractive tool is configured to subtract at least a portion ofsaid material from a surface of said mold such that said desired designis achieved in said surface of the mold.
 4. The three-dimensionalprinting system of claim 1, wherein said at least one positioningmechanism is in the form of at least one robotic arm which is configuredto position said at least one end effector.
 5. The three-dimensionalprinting system of claim 1, wherein said material is a plural componentmaterial such that said material is composed of at least two componentsincluding an activator mixture and a resin mixture.
 6. Thethree-dimensional printing system of claim 5, wherein said mixing headmixes said at least two components and dispenses said material.
 7. Thethree-dimensional printing system of claim 5, further including aproportioning system operably coupled to said at least one mixing headand configured to proportion said at least two components.
 8. Athree-dimensional printing system, comprising: a first positioningmechanism; a second positioning mechanism associated with said firstpositioning mechanism; a first end effector movably connected to saidfirst positioning mechanism and including at least one nozzle which isconfigured for dispensing a material layer-by-layer to form a mold; anda second end effector movably connected to said second positioningmechanism and including at least one subtractive tool which isconfigured for subtracting at least a portion of said mold.
 9. Thethree-dimensional printing system of claim 8, further including aproportioning system operably coupled to said at least one nozzle andconfigured to proportion said material.
 10. The three-dimensionalprinting system of claim 9, wherein said proportioning system furtherincludes a first mixer and a second mixer, said second mixer is fluidlyconnected to said at least one nozzle and located downstream of saidfirst mixer and upstream of said at least one nozzle.
 11. Thethree-dimensional printing system of claim 10, wherein said material iscomposed of a first component and a second component such that saidfirst mixer of said proportioning system mixes an accelerant and ablowing agent of said second component, and said second mixer mixes saidfirst component and said second component.
 12. The three-dimensionalprinting system of claim 11, wherein said proportioning systemselectively adjusts said blowing agent depending upon a desired densityof the material such that a material density of at least a first portionof a first layer of material is different than a material density of atleast a second portion of a second layer of material.
 13. Thethree-dimensional printing system of claim 8, wherein said at least onesubtractive tool is configured to subtract at least a portion ofmaterial from a surface of said mold such that a desired design isachieved in said surface of the mold.
 14. The three-dimensional printingsystem of claim 8, wherein said at least one first positioning mechanismand said at least one second positioning mechanism are respectively inthe form of at least one first robotic arm and at least one secondrobotic arm which are configured to respectively position said at leastone first end effector and said at least one second end effector.
 15. Amethod for 3D printing, comprising the steps of: providing athree-dimensional printing system including at least one positioningmechanism, and at least one end effector movably connected to said atleast one positioning mechanism and including at least one mixing headconfigured to dispense a material, and at least one subtractive toolconfigured to subtract at least a portion of said material; depositingsaid material by said nozzle layer-by-layer to form a mold; andsubtracting said material by said subtractive tool to subtract at leasta portion of a surface of said material in order to achieve a desireddesign on said mold.
 16. The method according to claim 15, furtherincluding a proportioning system operably coupled to said at least onenozzle and configured to provide at least two components to said atleast one nozzle such that said material is composed of said at leasttwo components.
 17. The method according to claim 16, wherein saidproportioning system further includes a first mixer and a second mixer,said second mixer is fluidly connected to said at least one nozzle andlocated downstream of said first mixer and upstream of said at least onenozzle.
 18. The method according to claim 17, further including a stepof selectively adjusting a density of the material such that a materialdensity of at least a first portion of a first layer of material isdifferent than a material density of at least a second portion of asecond layer of material.
 19. The method according to claim 18, whereinsaid density is adjusted by adjusting a blowing agent of one componentof said at least two components.
 20. The method according to claim 16,wherein said at least two components include an activator mixture and aresin mixture.